Make childShouldCreateRenderer into an SVG only concept

The only callers are in SVG, and removing this hook will encourage new 
element developers to use Shadow DOM and CSS instead of this magical 
backdoor. By doing so we make it easier to produce components that can 
be transitioned to JS or made into web components.

In merging the logic from SVGDocument and SVGElement into
RenderTreeBuilder I was also able to fix the SVGTests feature so that
it correctly disables rendering again so now the following tests pass:
svg/dynamic-updates/SVGSVGElement-dom-requiredFeatures.html
svg/dynamic-updates/SVGSVGElement-svgdom-requiredFeatures.html

Note: svg/custom/system-language-crash.html test seems to be a whitespace
difference that doesn't matter.

Review URL: https://codereview.chromium.org/137623004

git-svn-id: svn://svn.chromium.org/blink/trunk@165670 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[CSS Shapes] Image valued shape size and position should conform to the spec

Implement image valued shape-outside scaling and translation per the spec, http://dev.w3.org/csswg/css-shapes/#shapes-from-image:

"The image is sized and positioned as if it were a replaced element whose specified width and height are the same as the elements used content box size."

This change doesn't completely fulfill the spec, it's limited to image elements.

BUG=311388

Review URL: https://codereview.chromium.org/145603005

git-svn-id: svn://svn.chromium.org/blink/trunk@165671 bbb929c8-8fbe-4397-9dbb-9b2b20218538
More code problems detected by cppcheck

Another round this time running cppcheck with style flag on trunk codebase.

Review URL: https://codereview.chromium.org/143003016

git-svn-id: svn://svn.chromium.org/blink/trunk@165672 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove applyAuthorStyles flag from ShadowRoot.

Removing applyAuthorStyles flag from ShadowRoot's IDL.
We defer the internal clean up because the style resolver still depends on the implementation of applyAuthorStyles.

BUG=323130

Review URL: https://codereview.chromium.org/143993006

git-svn-id: svn://svn.chromium.org/blink/trunk@165673 bbb929c8-8fbe-4397-9dbb-9b2b20218538